1. Field
The disclosure may relate to mesh networks. More particularly, the disclosure may relate to a method and apparatus for flow control of data in a mesh network.
2. Background
In recent years, there has been an increase in demand for widespread access to high speed data services. The telecommunication industry has responded to the increase in demand by offering a variety of wireless products and services. In an effort to make these products and services interoperable, the Institute for Electrical and Electronics Engineers (IEEE) has promulgated a set of wireless local area network (WLAN) standards, e.g., IEEE 802.11. The products and services that conform to these standards are frequently networked in a wireless point to multipoint configuration. In one configuration, individual wireless devices (e.g., stations) may communicate directly with an Internet access point, with each of the wireless devices sharing the available bandwidth.
Another configuration may be a mesh network. A mesh network may be a distributed network having multiple wireless nodes. Each node may act as a repeater capable of receiving traffic, transmit or transport streams (TSs) and relaying the TSs to a next node. A TS may proceed from an origination node to a destination node by “hopping” from node to node. TS routing algorithms may insure that TSs are routed efficiently from their origination node to their destination node. TS routing algorithms may dynamically adapt to changes in the mesh network and may enable the mesh network to be more efficient and resilient. For example, in the event a node is too busy to handle the TS or a node has dropped out of the mesh network, the TS routing algorithm may route the TS to the destination node through other nodes in the network.
The destination node may be a mesh portal. TS arriving at the mesh portal may be decoded and reformatted for retransmission over other wired, or potentially wireless, networks, for example, the Internet. A traffic flow originating at a mesh node and traveling to the mesh portal may be referred to as an upstream traffic flow. A traffic flow originating at the mesh portal and traveling to a destination node may be referred to as a downstream traffic flow. A node one away from a mesh portal may be said to be a node of rank 1. Similarly, a node that requires at least two hops to reach a mesh portal may be said to be a node of rank 2. In general, a node that requires n hops to reach a mesh portal is said to be a node of rank n.
Large percentages of a mesh network's traffic flows may be upstream and downstream flows that terminate and originate at mesh portals. Upstream traffic flows may hop from higher ranked nodes to lower ranked nodes before departing through the mesh portal. Downstream flows may hop from lower ranked nodes to higher ranked nodes before reaching a destination node. Thus, lower rank nodes support the traffic flows of higher rank nodes. In general, nodes of rank 1 have more traffic flow than nodes of rank 2. Similarly, nodes of rank 2 have more traffic than nodes of higher ranks, such as 3, 4, 5, etc. Neighboring nodes may be defined as nodes one hop away from a reference node.
The mesh network, where lower rank nodes support upstream and downstream traffic flows from higher rank nodes, may often result in flow congestion at mesh nodes near the mesh portals. Many factors contribute to flow congestion including, but not limited to, neighboring nodes attempting to access the communication channel medium too frequently, neighboring nodes transmitting at lower data rates than optimum at the physical access layer, neighboring nodes transmitting bursts that occasionally exceed the negotiated access throughput, and poor radio conditions between the mesh node and the upstream nodes resulting in a lower than expected throughput, among other factors.